Once every year, on April Fool's Day, an unidentified villain robs one of Gotham City's banks of exactly $100,000. That thief is none other than Zelda The Great, a world-famous magician/escape artist who uses the ill-gotten gains to pay off a strange Albanian mastermind answering to the moniker of Eivol Ekdal, who devises Zelda's each and every escape device. The Batman decides to trap the thief by planting a story in the newspaper claiming the stolen money was counterfeit. When Eivol reads the fake article, he refuses to give Zelda his latest device, The Inescapable Death-Trap, until his demands are met.
Noticing a story about a rare gem on display in a local jewelry store (another phony article instigated by The Caped Crusader), E.E. send Zelda to swipe the gem in exchange for his creation. Zelda guesses the bugged-gem trick and confounds our heroes when she successfully steals the jewel — only to throw it away and then put through a phone call to Aunt Harriet and dupe her into believing her nephew Dick Greyson has been injured by a pop fly ball, and lure her to the Gotham playground. There Zelda kidnaps Harriet and spirits her away to her hide out, where she encases her in a straitjacket suspended over a vat of boiling oil, and holds her for ransom!!